P-38 can opener

A notch just under the hinge point keeps the opener hooked around the rim of the can as the device is "walked" around to cut the lid out.

The handle portion can also double as a makeshift flat-blade screwdriver, with limited ability because of the rather soft sheet metal used.

However, use of the metric system in the U.S. was not widespread at this point, and United States Army sources indicate that the origin of the name is rooted in the 38 punctures around the circumference of a C-ration can required for opening.

The larger P-51s are included with United States military "Tray Rations" (canned bulk meals).

They are also still seen in disaster recovery efforts and have been handed out alongside canned food by rescue organizations, both in the U.S. and abroad.

The device can be easily attached to a keychain or dog tag chain using the small punched hole.

Then, for a right-handed user, the P-38 is held in the right hand by the flat long section, with the cutting point pointing downward and away from the user, while also hooking the edge of the can through the circular notch located on the flat long section next to the cutting edge.

The P-38 is then returned to its stored location, whether that is dangling on a dog tag chain around one's neck, or in one's pocket if the P-38 is attached to a key ring.

A left-handed user is at a slight disadvantage in that the tip of the thumb (instead of the lateral flank of the distal index finger) must apply the combined travel & twist forces.

A similar device that incorporates a small spoon at one end and a bottle opener at the other is currently employed by the Australian Defence Force and New Zealand Army in its ration kits.